Whisk together flour, curry powder, and salt in a large bowl. Place in the bowl of a food processor fitted with the metal blade. Add shortening and margarine. Pulse until mixture is crumbly. Add cold water and pulse just until a dough forms. Do not over-process.

Roll dough on a floured wooden cutting board to 1/8-inch thickness. (At this point, you may cover the dough ball in plastic wrap and refrigerate overnight. Let rest at room temperature for 15 minutes before proceeding.) Cut circles 8 inches in diameter (use a paper template). Cover circles with plastic wrap until ready to use.

Stir breadcrumbs and beef stock into the ground beef. Cover and simmer 10 minutes, stirring occasionally, until all the liquid has been absorbed. It should not be watery, yet still remain moist. Remove from heat and let cool for 10 minutes.

Place 2 to 3 tablespoons of the meat filling in the center of each pastry circle. Moisten the edges of the circles, fold in half, and seal edges with the tines of a fork. Mix remaining water with the egg. Brush the tops of the patties with the egg wash.